| Message ID | 20221213160045.28170-2-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tools/xenstore: do some cleanup and fixes | expand |
On 13.12.2022 17:00, Juergen Gross wrote: > Today talloc_free() is not guaranteed to preserve errno, especially in > case a custom destructor is being used. > > Change that by renaming talloc_free() to _talloc_free() in talloc.c and > adding a wrapper to talloc.c. This looks to be stale ... > This allows to remove some errno saving outside of talloc.c. > > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > V2: > - drop wrapper (Julien Grall) ... after this change? Jan
On 14.12.22 10:54, Jan Beulich wrote: > On 13.12.2022 17:00, Juergen Gross wrote: >> Today talloc_free() is not guaranteed to preserve errno, especially in >> case a custom destructor is being used. >> >> Change that by renaming talloc_free() to _talloc_free() in talloc.c and >> adding a wrapper to talloc.c. > > This looks to be stale ... > >> This allows to remove some errno saving outside of talloc.c. >> >> Signed-off-by: Juergen Gross <jgross@suse.com> >> --- >> V2: >> - drop wrapper (Julien Grall) > > ... after this change? Oh yes, indeed. It should be replaced by: "So preserve errno in talloc_free()." Juergen
diff --git a/tools/xenstore/talloc.c b/tools/xenstore/talloc.c index d7edcf3a93..23c3a23b19 100644 --- a/tools/xenstore/talloc.c +++ b/tools/xenstore/talloc.c @@ -541,38 +541,39 @@ static void talloc_free_children(void *ptr) */ int talloc_free(void *ptr) { + int saved_errno = errno; struct talloc_chunk *tc; if (ptr == NULL) { - return -1; + goto err; } tc = talloc_chunk_from_ptr(ptr); if (tc->null_refs) { tc->null_refs--; - return -1; + goto err; } if (tc->refs) { talloc_reference_destructor(tc->refs); - return -1; + goto err; } if (tc->flags & TALLOC_FLAG_LOOP) { /* we have a free loop - stop looping */ - return 0; + goto success; } if (tc->destructor) { talloc_destructor_t d = tc->destructor; if (d == (talloc_destructor_t)-1) { - return -1; + goto err; } tc->destructor = (talloc_destructor_t)-1; if (d(ptr) == -1) { tc->destructor = d; - return -1; + goto err; } tc->destructor = NULL; } @@ -594,10 +595,14 @@ int talloc_free(void *ptr) tc->flags |= TALLOC_FLAG_FREE; free(tc); + success: + errno = saved_errno; return 0; -} - + err: + errno = saved_errno; + return -1; +} /* A talloc version of realloc. The context argument is only used if diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c index 476d5c6d51..5a174b9881 100644 --- a/tools/xenstore/xenstored_core.c +++ b/tools/xenstore/xenstored_core.c @@ -771,9 +771,7 @@ struct node *read_node(struct connection *conn, const void *ctx, return node; error: - err = errno; talloc_free(node); - errno = err; return NULL; }
Today talloc_free() is not guaranteed to preserve errno, especially in case a custom destructor is being used. Change that by renaming talloc_free() to _talloc_free() in talloc.c and adding a wrapper to talloc.c. This allows to remove some errno saving outside of talloc.c. Signed-off-by: Juergen Gross <jgross@suse.com> --- V2: - drop wrapper (Julien Grall) --- tools/xenstore/talloc.c | 21 +++++++++++++-------- tools/xenstore/xenstored_core.c | 2 -- 2 files changed, 13 insertions(+), 10 deletions(-)